#include <Eigen/Dense>
#include <iostream>

using namespace Eigen;

int
main()
{
	Matrix2d a;
	a << 1, 2, 3, 4;
	MatrixXd b(2, 2);
	b << 2, 3, 1, 4;
	std::cout << "a + b =\n" << a + b << std::endl;
	std::cout << "a - b =\n" << a - b << std::endl;
	std::cout << "Doing a += b;" << std::endl;
	a += b;
	std::cout << "Now a =\n" << a << std::endl;
	Vector3d v(1, 2, 3);
	Vector3d w(1, 0, 0);
	std::cout << "-v + w - v =\n" << -v + w - v << std::endl;
}
